Bug 915162

Summary:	AHCI disk drive (not CD-ROM) doesn't support the readonly=on
Product:	Red Hat Enterprise Linux 7	Reporter:	Sibiao Luo <sluo>
Component:	qemu-kvm	Assignee:	Virtualization Maintenance <virt-maint>
Status:	CLOSED NOTABUG	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.0	CC:	acathrow, chayang, flang, juzhang, kwolf, michen, pbonzini, qzhang, sluo, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-02-25 08:10:22 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Sibiao Luo 2013-02-25 06:03:44 UTC

Description of problem:
boot a guest with a AHCI disk drive (not CD-ROM) adding readonly=on, but the qemu will fail to boot up. while the AHCI(SATA) CD-ROM can support the readonly=on.

Version-Release number of selected component (if applicable):
host info:
kernel-3.7.0-0.34.el7.x86_64
qemu-kvm-1.3.0-5.el7.x86_6
guest info:
kernel-3.7.0-0.34.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.boot a guest with a AHCI disk drive (not CD-ROM) adding readonly=on.
e.g:...-device ahci,id=ahci1,bus=pci.0,multifunction=on,addr=0x8 -drive file=/home/my-data-disk.raw,if=none,media=disk,format=raw,id=drive-sata-disk,readonly=on -device ide-hd/ide-drive,drive=drive-sata-disk,id=sata-disk,bus=ahci1.0,unit=0
2.
3.
  
Actual results:
after the step 1,
guest fail to boot up with qemu prompt like: 
qemu-kvm: -device ide-hd,drive=drive-sata-disk,id=sata-disk,bus=ahci1.0,unit=0: Can't use a read-only drive
qemu-kvm: -device ide-hd,drive=drive-sata-disk,id=sata-disk,bus=ahci1.0,unit=0: Device 'ide-hd' could not be initialized

Expected results:

Additional info:

Comment 1 Paolo Bonzini 2013-02-25 08:10:22 UTC

The ATA standard does not support read-only hard disks.